The present invention relates to knife sharpeners, and in particular to a sharpener for knife blades used in industrial machinery and the like.
Knife blades are used in a wide variety of different types of industrial equipment, such as agricultural harvesters, tobacco choppers, vegetable and fruit peelers, wood chippers, and the like. Such devices are designed to cut a particular type of material, and typically include a releasable blade locking arrangement to remove the blades from the apparatus so that they can be periodically cleaned and sharpened.
A great many of these machinery blades are quite large, such that special techniques must be employed to properly sharpen the same. For example, the blades of a wood chipping device used in milling lumber are in the nature of 24 inches long, five inches wide, one-half inch thick, and weigh approximately 25 pounds. These blades are constructed of a high carbon steel to retain a sharp edge. However, due to the harsh treatment which they receive during use, the blades must be removed from the chipper and sharpened after every few hours of operation. Further, a great number of such cutting machines employ a plurality of blade sets, each having a different cutting angle, to adapt the machine to efficiently cut the wood or other product when the physical characteristics thereof, such as moisture content, seasoning, and the like, vary. Hence, sharpeners for such cutting blades preferably include means which enable the same to quickly alter the sharpening angle so as to facilitate the sharpening of the different blade sets.
Tool grinders are available for sharpening industrial knife blades. However, the same are quite massive and very expensive devices, which have a degree of precision which is not required to properly sharpen the above described type of industrial machinery blades. Heretofore, such sharpeners were in the nature of very precise machine tool grinders, with extremely accurate meonite, hand scraped ways in which the translating portions of the grinder are mounted. The grinder head of such devices are typically stationary, and include a traveling bed or table on which the blades are mounted. The ways have force fed lubrication, so that the edge of the knife blades can be very exactly ground to a close tolerance in the nature of a few thousandths of an inch, such as is required for paper cutters and veneer knives. Such precision tool grinders are not only expensive, but are also incapable of being set up quickly and/or easily adapted to accommodate different sharpening angles. Also, the precision grinders are designed for operation in a relatively clean tool room environment, as opposed to the processing areas in which the wood chipping machines are used, such as a wood mill.